Observatory dome structures have been known and used for many years. They provide shelter from the elements and protection from the wind for both the astronomer and the delicate telescopic equipment. However, the prior art designs have required the construction of very expensive large permanent structures with extremely complex mechanisms for the movement of the shutter and the rotation of the dome. This has placed an observatory dome structure out of the reach, and the pocketbook, of an amateur astronomer.
Some attempts have been made to construct small domes for the use of the backyard astronomer. However, these domes have required the construction of permanent buildings for the dome structure to be placed upon. These buildings have tended to be large solid masonry structures so that the weight of the dome could be supported, particularly during rotation.
Observatory dome structures have been made from a variety of materials. Metal or wooden domes have required the use of many parts and a strong frame for supporting the skin of the dome. With fiberglass domes, there has been a difficulty with the transportation of the domes, due to large diameter pieces with curvilinear shapes, and the need to use chemical welding to join the parts.
The equipment needed to permit the dome to rotate freely in a 360 degree path has been bulky and complex. Such a rotatable dome system is shown in U.S. Pat. No. 2,846,962.
Observatory dome structures contain an opening through which the telescope is pointed. The opening preferably is of a size and shape, generally rectangular, so as to permit the telescope to be rotated from the horizontal position to the vertical position. The opening is closed with a shutter or shutters when the telescope is not in use. The shutters conform to the opening and are usually rectangular in shape. This creates a major problem in dome shutter design in that the opening is rectangular, is significantly greater in length than in width, and is longer than half the surface available on the dome. Thus, a single piece shutter cannot be stored on or adjacent to the dome structure surface without hanging over the edge creating interference with the rest of the structure and exposing the shutter edge to the detrimental effects of the wind.
One prior art solution to this problem has been to move the shutter sideways or horizontally, either as a single piece or as split halves as shown in U.S. Pat. Nos. 3,370,380; 3,359,682 and 2,996,844. This type of horizontal movement of the shutter requires that the shutter or shutters be mounted on a rail system with the use of complex mechanical systems to effect movement of the top and bottom of the shutter at the same time. Additionally, the shutter is exposed to the wind, requiring a very strong structure to be able to physically hold it in place. The long joint that the shutter makes with the dome, and for a split shutter, with itself, is prone to leakage.
The use of the prior art vertical operating shutters have also had a host of problems. A one piece vertical shutter, such as that depicted in U.S. Pat. No. 3,213,571, must be able to pivot away from the observatory dome structure, greatly increasing the complexity of the equipment and the wind resistance of the structure. The use of a two piece shutter system that moves vertically has similar problems with the storage of the shutter in the open position and wind resistance. Additionally, each half must move more than its own length. Moving both pieces at the same time doubles the complexity of the mechanism used, particularly if separate motor systems are to be coordinated. Furthermore, since the bottom, or front shutter must move through the space occupied by the top shutter, restrictions are placed on the drive and guideway system.
It has now been discovered that a prefabricated observatory dome structure can be constructed from a modular wall system, a dome of connected panels, and a three part shutter with an opening and latching system, so that the backyard astronomer can have an effective wind and weather resistant observatory.